1. Technical Field
The invention related to a coupling element for a single wire or multi-wire electrical cable and a method of producing the same. The coupling element comprises a contact support to which a protective body surrounding the cable connection is molded in such a way that a region of the surface of the contact support remains exposed. The exposed region has openings extending through the contact support and contacts that are conductively connected with a wire of the cable arranged in the openings.
2. Description of the Related Art
Coupling elements, which can include pin-type connectors as well as female receptacles, are generally used to connect multi-wire electrical cable in the automobile industry. Such connectors provide, for example, a connection between the anti-lock braking system (ABS) or the electrical braking system (EBS) of a trailer and the tractor. If the cables between the vehicles are exposed, then the coupling elements are exposed to dirt, splash water, shock and tensile loads. It is therefore advantageous to use a mechanically robust construction that protects against moisture and dirt.
The utility model DE 94 10 092 discloses a coupling element wherein a protective body is molded to the contact support holding the electrical contacts in place. The protective body surrounds the cable or at least the section of the cable in which the jacket has been removed to electrically connect to the contacts, and also the marginal edge of the jacket. The protective body thereby forms a mechanical protection for the contact support as well as a strain relief for the cable while simultaneously sealing the cable. The contacts have to remain free of the molding material in order to provide a reliable connection with close tolerances between the coupling element and a mating element.
The region of the contact support in which the contacts are arranged, has a predetermined shape and can comprise raised portions, recesses or guides to connect to and lock with the mating element. The edge region of the contact support is typically sealed by a circumferential seal that is arranged, for example, in a groove disposed on the front face of the contact support. During operation, the coupling element is engaged with a complementary mating element that closes the seal. With this arrangement, dirt cannot accumulate in the contact region, and moisture is prevented from entering the coupling element along the contacts. Although it would be possible to seal only the individual contacts against the liquid molding material, it is preferred to keep the entire region near the seal and the contacts free of molding material to ensure a precise fit with the mating element.
It is difficult to seal the openings of the contact support in the area of the contacts. The contacts are typically inserted into and secured in the openings with a locking element. The contacts frequently have recesses or a shape that is not complementary to the cross-section of the opening. Consequently, the seal is not tight. To prevent the molding material from penetrating the openings when the protective body is formed, the DE-GM 94 10 092 proposes to hermetically seal the openings individually with separate sealing elements. Alternatively or in addition, a hot melt adhesive can also be used to form the seal.
Disadvantageously, however, sealing the openings is very labor intensive, with the costs increasing for multi-wire cables according to the number of wires. Also, the fabrication of the protective body of conventional couplings requires a comparatively large amount of molding material which raises the weight and the production costs.